Intravascular filter cut from sheet metal

ABSTRACT

The present disclosure describes filter devices for deployment to body vessels where clots or emboli may need to be captured, particularly the vena cava. The filter device is of unitary construction, having been cut from a substantially planar sheet of a metal, in some instances a shape memory metal. The device has a construction including a plurality of petals, the petals containing an inner rib which curves in the deployed state. A method of making a filter device is also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application from U.S. Non-Provisionalapplication Ser. No. 15/370,382, filed on Dec. 6, 2016, which claims thebenefit of priority under 35 U.S.C. § 119(a) to U.S. ProvisionalApplication No. 62/270,821, filed Dec. 22, 2015 all of which are herebyincorporated by reference in their entirety.

BACKGROUND

The present invention relates to medical devices. More particularly, theinvention relates to a vena cava clot filter that can be percutaneouslyplaced in the vena cava of a patient.

A need for filtering devices arises in trauma patients, orthopedicsurgery patients, neurosurgery patients, or in patients having medicalconditions requiring bed rest or non-movement. During such medicalconditions, the need for filtering devices arises due to the likelihoodof thrombosis in the peripheral vasculature of patients wherein thrombibreak away from the vessel wall, risking downstream embolism orembolization. For example, depending on the size, such thrombi pose aserious risk of pulmonary embolism wherein blood clots migrate from theperipheral vasculature through the heart and into the lungs.

A filtering device can be deployed in the vena cava of a patient when,for example, anticoagulant therapy is contraindicated or has failed.Typically, filtering devices are permanent implants, each of whichremains implanted in the patient for life, even though the condition ormedical problem that required the device has passed. In more recentyears, filters have been used or considered in preoperative patients andin patients predisposed to thrombosis which places the patient at riskfor pulmonary embolism.

Currently available vena cava filters generally include a number ofstruts formed from individual pieces of wire arranged to give the filterits shape and collected at one end by a separate piece that gathers theends of the struts together, such as a collet, a bushing, or a sleeve,generally referred to as a hub. Although these devices are effective,their construction could be simplified.

There is a need for filter devices which are simple to make and providegeometries that are efficacious for capturing emboli and clots.

BRIEF SUMMARY

In one aspect, the present disclosure provides a filter device forimplantation into a body vessel, the device having a hub; and aplurality of struts extending radially from the hub, each strut having afirst end connected to the hub and extending radially therefrom to asecond end, the second ends of two radially adjacent struts beingconnected at a tip to form a petal having a gap between the radiallyadjacent struts, each petal comprising an inner rib extending from thehub through the gap to the tip of the petal.

In another aspect, the present disclosure describes a filter device forimplantation into a body vessel, the device having a hub which is acenter ring. The device also includes a plurality of struts extendingradially from the hub, each strut having a first end connected to thehub and extending radially therefrom to a second end, the second ends oftwo radially adjacent struts being connected at a tip to form a petalhaving a gap between the radially adjacent struts, each petal comprisingan inner rib extending from the hub through the gap to the tip of thepetal. The device includes a pad at each petal tip for contacting thewall of the body vessel, each pad comprising a barb for engaging thewall of the body vessel. The filter device is of unitary constructionand being cut from a substantially planar piece of a shape memory metal.

In another embodiment, the present disclosure provides a method ofmaking an intravascular filter device. The method includes steps ofcutting a substantially planar piece of material to form a filterdevice, the filter device comprising a hub and a plurality of strutsextending radially from the hub, each strut having a first end connectedto the hub and extending radially therefrom to a second end, the secondends of two radially adjacent struts being connected at a tip to form apetal having a gap between the radially adjacent struts, each petalcomprising an inner rib extending from the hub through the gap to thetip of the petal, the filter device being in a flat configuration;placing the filter device at a distal end of a tubular mandrel having alumen formed therethrough, the mandrel having a proximal end andextending to the distal end; and pulling the filter device through thedistal end in the proximal direction and into the lumen such that thefilter device adopts a expanded configuration by contact with themandrel.

Further objects, features, and advantages of the present invention willbecome apparent from consideration of the following description and theappended claims when taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings are purely schematic illustrations of various aspects ofthe invention and are not necessarily to scale, unless expressly stated.

FIG. 1 is a perspective view of a filter in a expanded configuration ordeployed configuration in accordance with one embodiment of the presentinvention;

FIG. 2 is a view of the filter device of FIG. 1 in its flatconfiguration in accordance with the principles of the presentdisclosure;

FIG. 3 is a side view of the filter device of FIGS. 1 and 2 in itsexpanded or deployed configuration;

FIG. 4 is a view of a second embodiment of a filter device in its flatconfiguration in accordance with the principles of the presentdisclosure;

FIGS. 5A-5C are closeup views of barbs formed for a filter device inaccordance with the principles of the present disclosure;

FIGS. 6A-6C are closeup views of centers of various embodiments offilter devices in their flat configurations and which are constructed inaccordance with an embodiment of the present disclosure;

FIG. 7A is a side view of a petal of a filter device in its deployedconfiguration in accordance with an embodiment of the presentdisclosure;

FIG. 7B is a side view of the petal of FIG. 7A in its compressedconfiguration;

FIG. 8A is a side view of a filter device deployed to a blood vessel anda retrieval sheath;

FIG. 8B is a side view of the filter device of FIG. 8A being pulled intothe retrieval sheath; and

FIGS. 9A-9D are side views of a filter device constructed in accordancewith the principles of the present invention being converted from itsflat configuration to its expanded configuration using a tubular mandrelin accordance with the principles of the present disclosure.

DETAILED DESCRIPTION

While the present invention has been described in terms of certainpreferred embodiments, it will be understood that the invention is notlimited to the disclosed embodiments, as those having skill in the artmay make various modifications without departing from the scope of thefollowing claims.

The terms “substantially” or “about” used herein includes variations inthe recited characteristic or quantity that are functionally equivalentto the quantity recited, such as an amount that is equivalent to thequantity recited for an intended purpose or function. In the case of anumerical quantity, the terms “substantially” or “about” shall mean arange consisting of a value 20% less than the recited value to a value20% greater than the recited value, inclusive.

As used herein, the terms “upstream” and “downstream” particularly referto the direction of blood flow through a vessel. Blood flows fromupstream to downstream. Reference made to an upstream or downstream endor portion of a filter device is done with reference to the deployedconfiguration of the device, with blood moving from the upstream endtoward the downstream end of the device when the device has beendeployed to a blood vessel.

As used herein, the terms “expanded configuration” and “deployedconfiguration” are to be understood as substantially interchangeablewith regard to the shape of a filter device. Typically, the expandedconfiguration and the deployed configuration are substantiallyidentical; “expanded” being used to describe the device when it has beenshaped out of its flat configuration but not necessarily deployed to abody vessel, and “deployed” being used to describe a device which isresident in a blood vessel. A person of skill in the art will recognizethat any dissimilarity between the expanded configuration and thedeployed configuration will arise from the constraint applied by thewall of the vessel to which the filter device has been deployed.

As used herein, the term “unitary construction” refers to the structuralcomponents of a filter device, such as a strut, a hub, a barb, a padstructure, all being formed from the same piece of precursor material,preferably a substantially planar piece of a metal, the metal preferablybeing a shape memory alloy. Non-structural components, such as coatings,radiopaque markers, and the like, may be added to the device withoutdetracting from the unitary construction of the structure of the device.

FIG. 1 illustrates a first embodiment of a filter device 10 inaccordance with the principles of the present disclosure. The filterdevice 10 is shown in its expanded configuration 11 and comprises aplurality of struts 12, which each have a first end 37 attached to acenter or hub 16. It should be noted that unlike certain devices alreadyknown in the art, the hub 16 is not a separately-formed piece whichgathers ends of struts in, for instance, a collet or a sleeve; rather,as used herein, a hub is a portion of a unitary device from which strutsgenerally emanate.

The struts 12 extend from first ends 37, which are connected to the hub16, radially outward to second ends 38. In one embodiment, the struts 12comprise first segments 20 and angle at second segments 24. In oneembodiment, the first segments 20 of two radially adjacent struts 12 areconjoined, as illustrated in FIG. 1, but first segments 20 may be formedseparately from one another as well. In the embodiment of FIG. 1, thefirst segments 20 disjoin and angle to form second segments 24 at split22.

Two radially adjacent struts 12 comprise petals 26. The petals 26 eachdefine a gap 27 between the two radially adjacent struts 12, with thesecond ends 38 of struts 12 converging at tip 32. It is noted that inFIG. 1, the radially adjacent struts 12 that have conjoined firstsegments 20 form portions of two different petals 26, and the struts 12which form a single petal 26 are not conjoined at their first segments.

As shown in FIG. 1, the device comprises four petals 26. However, othernumbers of petals are possible when the device has radial symmetry,including three petals, five petals, six petals, seven petals, eightpetals, nine petals, 10 petals, 11 petals, 12 petals, 14 petals, 16petals, 18 petals, 20 petals, 22 petals, and 24 petals.

Pad structure 34 is present at tip 32 of petal 26 in the embodiment ofFIG. 1. The pad structure is a perforation preventing pad, and isdesigned to lay flat against the wall of a vessel to which the filterdevice has been deployed in order to allow the barbs 36 of the device toengage the wall, but not perforate it to such a degree to cause injury.As shown in FIG. 1, the pad structure 34 is shown as oval or ellipticalin shape, but any polygonal or ring shape can be employed so long as thefunction of the pad 34 is retained.

Barb 36 of device 10 of FIG. 1 is located downstream of pad structure34. The barbs 36 of this disclosure will be described in detail withregard to FIGS. 5A-C. The function of the barbs 36 is to engage the wallof the vessel in order to prevent migration of the device.

The inner rib 28 is located in gap 27 of petal 26. The inner rib 28extends from hub 16 to tip 32, and comprises curves with peaks 29, 30,and 31, which gives the inner rib 28 a greater overall length than thestruts 12.

The inner rib 28 provides the filter device 10 with a number ofabilities. Foremost, each inner rib 28 adds a solid portion within eachpetal 26, providing more connections to hub 16 and thus providing thefilter device 10 with more surface area on which to catch smaller clotsor emboli. The inner rib 28, because of its curved nature, also servesto accommodate foreshortening when the filter device 10 is put into itscompressed configuration and loaded into a delivery system. Thecurvature of the inner rib 28 provides sufficient slack for packaging ofthe device 10, but is not so long as to increase the profile of thedevice in the compressed configuration. As will be shown later, innerrib 28 straightens when the device is in its compressed form in thedelivery device.

The inner rib 28 may be of a number of designs. In one embodiment, it issinuous and curved but does not have three peaks. The inner rib 28 maybe of any configuration as long as the length of inner rib 28 is greaterthan or equal to the length of the petal 26 in which it resides when thedevice is in its compressed configuration.

The inner rib 28 reinforces the filter device 10 and provides additionalradial force against the wall of a vessel to which the filter device 10has been deployed. As a result, filter apposition is improved, and thechances of migration of the filter are minimized. Further, the inner rib28 may serve as a redundant structure; should a strut of the petal 26 inwhich the inner rib 28 resides fail for any reason, the filter device 10should still function and remain in place, and will still beretrievable.

The hub 16, as shown in FIG. 1, is a ring with empty center 18.Alternate designs are possible and will be described later. An emptycenter 18 will be accommodating of retrievability, such that a retrievalassembly with an element such as a hook will be able to engage thecenter and snare the filter device 10 so as to more surely guaranteeretrieval.

In another embodiment, the empty center 18 may be provided such that aretrieval member may be attached to the device after assembly of thefilter device 10. Such a retrieval member may be, for instance, a hookthat can be fit through the empty center 18 and welded or soldered intoplace. This would allow for simplified grasping by a retrieval snare.

FIG. 2 illustrates the flat configuration 14 of device 10 of FIG. 1. Inthis illustration, the four petals 26 and the overall radial symmetry ofthe device can be seen. The peaks 30,31 of the curved inner rib arepresent, showing their residence in gap 27 of the petals 26. Overall,cutting from a sheet of metal rather than a cannula results in theability to create more complex geometries such as the central hub 16,the inner rib 28, and the perforation preventing plates 34. FIG. 3provides a side view of the device 10 of FIGS. 1 and 2 in expandedconfiguration 11.

In one embodiment, a self-expanding intravascular filter in accordancewith the principles of the present disclosure can be made of a shapememory material. One example of a shape memory material is a shapememory metal, in particular a class of nickel-titanium alloys, includingthose marketed under the name NITINOL. Such alloys are known for theirshape memory and pseudoelastic properties. As a shape memory material,such a nickel-titanium alloy is able to undergo a reversiblethermoelastic transformation between certain metallurgical phases. Adevice made from a shape memory material, in some embodiments anickel-titanium alloy, can be heat set to retain its shape afterimplantation.

In another embodiment, a filter device may be made of a stainless steel,such as stainless steel 304.

The device is particularly envisioned to be of unitary construction. Inone sense, a device of unitary construction is made of a single piece ofprecursor material, such as a substantially planar sheet of metal.Specifically, a sheet of a shape-memory metal such as a nickel-titaniumalloy may be laser-cut to yield the filter device. Unitary constructionand laser cutting allows for the use of a single pattern to generate thedevice without the complications and possibilities for introduction oferror that derive from weaving, soldering, or using another method toconnect separate parts into a unit. As used herein, the term “unitary”means that the device is made of a single piece which has not beenjoined to another piece.

Turning now to FIG. 4, an alternative embodiment of a filter device inaccordance with the principles of the present disclosure is attached.Numerous aspects of the device can be altered and fall within theprinciples of the invention. Regarding FIG. 4, device 110 has six petals126 radially surrounding the hub 116, and the barbs 136 are configureddifferently than the device of FIGS. 1-3.

To further support the anchoring of the filter device to the vessel,hooks or barbs may be incorporated onto the outer surface of the device.FIG. 5A-C illustrate a number of barbs which will permit anchoring of adevice to a vessel wall. In a preferred embodiment these barbs may becut from the structure and bent outward.

FIG. 5B illustrates barbs in accordance with embodiment shown in FIGS.1-3. Here, the barb 36 is bent out of the plane of the rest of thedevice 10 and lies upstream of the pad structure 34.

FIGS. 5A and 5C show barb configurations in which the barb is cut from aspace within the pad structure. The barb 136 of FIG. 5A is formed fromwithin pad structure 134 and points with its point in the downstreamdirection, whereas barb 536 of FIG. 5C is formed within pad structure534 but points with its point in the upstream direction. In either case,the barb 136/536 will be bent out of the plane of the pad 134/534 inorder that the barbs 136/536 can engage the wall of a vessel V intowhich the device 110/510 is implanted.

Barbs may face the upstream direction, which will not interfere withretrieval. However, if a more secure hold is desired and the barbs aredesigned to be bent back such that their pointed ends point back in thedownstream direction, the filter device, and particularly the petals,need to have a concave geometry so that retrieval can proceed as shownin FIG. 8B.

It is intended that any of the barb configurations shown in FIGS. 5A-5Ccan be combined with any other design of the filter device and stillfall within the scope of the present invention. In one embodiment, thebarb configurations may vary on a petal-to-petal basis; that is, onepetal may have a barb as in FIG. 5B, and the radially adjacent petal mayinclude a barb as in FIG. 5A.

FIG. 6A-C illustrate various structures that can be used at hubs. Hub116 is similar to the hubs shown in the embodiments of FIGS. 1-4,wherein the hub is a ring shape with an aperture 118 formedtherethrough. As mentioned previously, this open aperture 118 may aid insimplifying retrieval of the filter device from a vessel to which it hasbeen deployed, as a retrieval member such as a hook or a snare can befed therethrough. The embodiment of FIG. 6C is similar, with the hub 316having a polygonal shape, in this case a hexagonal aperture 318 withedges 317 is formed therethrough.

FIG. 6B shows a device having hub 216, which is a closed circle 218.Such a hub configuration may be preferred for an embodiment of a filterdevice which is not to be retrieved, and the closed end may assist inincreasing the capacity of the filter to capture clots or emboli.However, a snare which targets a different portion of the filter devicecould be used, and therefore a device having hub 216 with closed circle218 could still be a retrievable filter.

The outer diameter of the hub 16/116/216/316 may be limited by the sizeof the sheath of the delivery system. In various embodiments, diameterof the hub may range from about 7 french to about 15 french, or fromabout 2.5 millimeters to about 5 millimeters.

Turning now to FIG. 7A, a petal 126 in accordance with one embodiment ofthe present disclosure is illustrated. The petal is part of a device ina deployed configuration or an expanded configuration 170. When thedevice is in this configuration, the struts take on arcuate shape 120,and inner rib 128 takes on a sinuous shape, the inner rib 128 beingcurved such that curve peaks 129, 130, and 131 are evident. As mentionedpreviously, the curved rib increases clot capture area, increase radialforce produced, strengthens the device, acts as a redundant feature incase of failure of a strut, and accommodates foreshortening.

In contrast, FIG. 7B shows the petal of FIG. 7A is shown in itscompressed configuration 180 and is referred to as compressed petal 196.As mentioned previously, the typical situation in which a device of thisconstruction will be in its compressed configuration is when the deviceis packed into and loaded in a delivery apparatus prior to delivery intothe vasculature of a patient. In this configuration, compressive force185 as applied to the device, and the struts take on straightened shape190. Notable is the straightening of the inner rib 128 to substantiallystraight configuration 198. In some cases, such as that illustrated, thestraightening may be so extensive that the peaks of any curve may nolonger be evident.

With regard to retrieval of the device, FIG. 8A shows deployed device410 in a blood vessel. Barbs 436 engage the wall of vessel V, and padstructures 434 prevent the barbs 436 from puncturing the vessel wall.Because the device is in deployed configuration 470, the inner rib 428is sinuous in shape.

In FIG. 8B, retrieval sheath 450 has moved in direction 451 to capturethe filter 410. Not shown is an optional retrieval member, such as ahook, for engaging the hub. The concave profile of the filter device410, particularly owing to the shapes of petals 426, increasesretrievability. During retrieval, the inner rib straightens to straightconfiguration 498, and the barbs 436 move toward the axial center ofvessel V. This minimizes or prevents contact between the barbs 436 andthe retrieval sheath 450, such that the points of the barbs do notdamage the retrieval sheath 450. In some embodiments, the barbs 436 maymove through and past the longitudinal axis of the vessel V. Any varietyof device configurations which avoid contact between the barbs 436 andthe retrieval sheath are possible.

The device may, optionally, further incorporate radiopaque markers toassist a physician with placement in the body. Many suitable radiopaquematerials are known and any of these may be selected for use with adevice of the present disclosure. The radiopaque markers may be made ofmaterials including gold, palladium, tantalum, platinum, andbiocompatible alloys of any of these materials.

Further, a device as disclosed herein may be used with many existingdelivery systems as are known in the art. Particularly when a device ismade of a shape memory metal such as a nickel-titanium alloy, the finaldimensions of the device are determined by the remembered state and notdependent upon manipulating the delivery system to crimp or otherwisemodify the device as it is being loaded.

Many possible variations on a device of this construction are alsopossible. If desired, the filter device may be covered with a porous ornon-porous layer which has drug-eluting properties. All coatings orbiological coverings may be attached by any known method, includingspray coating and the like.

A device in accordance with the principles of the present disclosure maybe made according to a series of steps, as illustrated in FIGS. 9A-9D.As mentioned previously, a single, monolithic, sheet of a shape memoryalloy may be precisely laser cut to generate the overall shape of thefilter device.

In FIG. 9A, a device 610 in its flat configuration 614 has been placedat a distal end 626 of a substantially tubular mandrel 660. The device610 makes contact at the open end of the tubular mandrel 660 at pointsof contact 671. In FIG. 9B, the device 610 has been drawn partially intothe lumen of the tubular mandrel 660 by pulling in a direction 681 toform partially expanded configuration 680. FIG. 9C illustrates thecontinued effect of the pulling force in direction 681, which convertsthe device to partially expanded configuration 682. Finally, in FIG. 9D,the device has achieved expanded configuration 611 due to the continuedaction of pulling force in direction 681. Optionally, and particularlywhen a shape memory alloy is used for the device, the device may be heatset by providing heat 669.

The mandrel 660 may be a simple tubular structure, or it may be of acustom shape in order to achieve specific shapes of the device 610. Forexample, the mandrel 660 of FIGS. 9A-9D is illustrated with a flared end662 to give the mandrel 660 an overall trumpet-like shape. Many otherconfigurations are possible, including frusto-conical mandrels, and soforth.

In some embodiments, shaping or bending the filter into its expandedconfiguration may include passing the filter device through a pluralityof mandrels.

A method of using a filter device as described in the instant disclosurecan include a number of different steps. In one step, the filter devicemay be compressed to a compressed state and loaded into a deliveryassembly. The delivery assembly may be introduced to the bodypercutaneously, and the device delivered, such as by a pusher, into thelumen of the body vessel, in one embodiment the vena cava, moreparticularly the inferior vena cava. The filter device, upon deployment,will anchor against the vessel wall as it is deployed from the deliveryassembly as it returns to its remembered, unconstrained state. Forinstance, in the illustration of the filter device deployed to a bodyvessel of FIG. 8A, the device after removal from the delivery assemblyhas returned to its unconstrained remembered state, leading to anexpansion at the upstream, open end of the filter 410, with the barbs436 engaging the vessel wall to secure the device within thevasculature. Delivery may be guided by imaging which may optionallyinclude monitoring of one or more radiopaque portions included on thedevice. After the device has been secured within the body vessel, thedelivery assembly is removed from the patient.

While the present invention has been described in terms of certainpreferred embodiments, it will be understood that the invention is notlimited to the disclosed embodiments, as those having skill in the artmay make various modifications without departing from the scope of thefollowing claims.

The invention claimed is:
 1. A filter device for implantation into abody vessel, the device comprising: a hub; and a plurality of strutsextending radially from the hub, each strut having a first end connectedto the hub and extending radially therefrom to a second end, the secondends of two radially adjacent struts being connected at a tip to form apetal having a gap between the radially adjacent struts, each petalcomprising an inner rib extending from the hub through the gap to thetip of the petal, wherein the plurality of struts extend radiallyoutward from the hub, such that the first ends of the plurality ofstruts that are connected to the hub extend further in a radiallyoutward direction, compared to an axially distal direction.
 2. Thefilter device according to claim 1 wherein the filter device is ofunitary construction.
 3. The filter device according to claim 1 whereinthe filter device comprises a shape memory material.
 4. The filterdevice according to claim 3 wherein the shape memory material comprisesa nickel-titanium alloy.
 5. The filter device according to claim 1comprising a barb at each tip.
 6. The filter device according to claim 1further comprising a pad structure adjacent a tip of a petal.
 7. Thefilter device according to claim 6 comprising a barb, the barb beingformed by a plurality of cuts of the pad structure.
 8. The filter deviceaccording to claim 1 having a deployed state and a compressed state, theinner rib comprising a curve in the deployed state and beingsubstantially straight in the compressed state.
 9. The filter deviceaccording to claim 1 wherein the struts have an arcuate shape.
 10. Thefilter device according to claim 1 wherein the hub is a ring.
 11. Thefilter device according to claim 1 wherein the hub is a solid circle.12. The filter device according to claim 1 wherein each strut comprisesa first segment extending from the first end away from the hub, eachfirst segment being conjoined with a radially adjacent first segment.13. The filter device according to claim 12 wherein the first segmentsthat are conjoined are portions of two petals.
 14. A filter device forimplantation into a body vessel, the device comprising: a hub comprisinga center ring; a plurality of struts extending radially from the hub,each strut having a first end connected to the hub and extendingradially therefrom to a second end, the second ends of two radiallyadjacent struts being connected at a tip to form a petal having a gapbetween the radially adjacent struts, each petal comprising an inner ribextending from the hub through the gap to the tip of the petal; and apad at each petal tip for contacting the wall of the body vessel, eachpad comprising a barb for engaging the wall of the body vessel; thefilter device being of unitary construction made from a single piece ofprecursor material and being cut from a substantially planar piece of ashape memory metal.
 15. A method of forming a filter device forimplantation into a body vessel, the method comprising: cutting asubstantially planar piece of material to form a filter device, thefilter device comprising a hub and a plurality of struts extendingradially from the hub, each strut having a first end connected to thehub and extending radially therefrom to a second end, the second ends oftwo radially adjacent struts being connected at a tip to form a petalhaving a gap between the radially adjacent struts, each petal comprisingan inner rib extending from the hub through the gap to the tip of thepetal, the filter device being in a planar configuration; and bendingthe filter device to form an expanded configuration.
 16. The methodaccording to claim 15 wherein bending the filter device comprisesplacing the filter device in a planar configuration at a distal end of atubular mandrel having a lumen formed therethrough, the mandrel having aproximal end and extending to the distal end; and moving the filterdevice through the distal end into the lumen and toward the proximal endsuch that the filter device adopts the expanded configuration by contactwith the mandrel.
 17. The method according to claim 16 wherein thefilter device is moved through a plurality of mandrels.
 18. The methodaccording to claim 16 further comprising a heat setting step.
 19. Themethod according to claim 15 further comprising cutting a barb in thefilter device.
 20. The method according to claim 19 comprising a step ofbending the barb outward.